Complex. Complicated. Confusing. Beyond comprehension. Two prominent Democrats used these words this week to describe the Affordable Care Act, or "Obamacare."

One of those Democrats, Sen. Jay Rockefeller (D-W.V.), was one of the key architects of the law. The other, Health and Human Services Secretary Kathleen Sebelius, is in charge of implementing the law.

"I believe that the Affordable Care Act is probably the most complex piece of legislation ever passed by the United States Congress. Tax reform obviously has been huge too, but up to this point it is just beyond comprehension," Rockefeller said Tuesday at a Senate Finance confirmation hearing, according to The Washington Examiner's Paul Bedard.

Rockefeller also warned Marilyn Tavenner, who has been appointed to serve as the administrator of the Centers for Medicare & Medicaid Services, that the ACA is "so complicated and if it isn't done right the first time, it will just simply get worse."

Sebelius was speaking at a Monday forum hosted by the Harvard School of Public Health and Reuters.

When asked about the challenges of implementing the ACA, Sebelius said, "I think that, probably, no one fully anticipated, when you have a law that phases in over time, how much confusion that creates for a lot of people."

Sebelius also expressed disappointment in the fact that there are some who continue to believe that the ACA is a bad law and do not want it to be implemented. After the U.S. Supreme Court upheld most of the law and Barack Obama was re-elected, she expected the law's opponents to begin supporting it.

"The politics has been relentless and continuous. ... There was some hope that once the Supreme Court ruled in July and then once an election occured there would be the sense that, this is the law of the land, let's get on board, let's make this work. And yet, we find ourselves still having, sort of, state by state political battles. And, again, creating what I think is a lot of confusion," she complained.

During the debate over passage of the ACA, one criticism was that it would be too complicated. Some of the alternatives that were suggested at the time, such as providing vouchers or individual tax deductions for the purchase of health insurance, were advocated, in part, for their simplicity.

The ACA has run into a series of difficulties in its implementation. The 2,700 page bill already has 17,000 pages of regulations, and counting.

In 2011, HHS decided it had to abandon implemenation of the CLASS program, which was supposed to be a source of revenue to help pay for the ACA. There have been dozens of lawsuits over Sebelius' birth control mandate. Some Republican governors have decided not to implement the Medicaid expansion. Many states have opted to have the federal government implement the health care exchanges. And, many businesses appear to be opting to no longer offer health insurance for their employees and pay the penalty instead (which is actually just a tax, according to the Supreme Court); this, in turn, will place even greater strain on the government-run exchanges.